Homebrew PCBs

It'd be interesting if your thought works.


Some ideas than might help you with the alignment of the holes:
- Increase the size of the holes and the space around it so that you 
have greater tolerance
- Add two more holes in two edges of your board for centering. Drill 
those in both boards (so in total 4), glue your boards together and line 
them with a nail or similar (while the glue isn't dried).
After the glue has dried you should then be able to drill all the other 
holes with a very good precision.


Maybe this helps you.


Simon




Am 05.07.2015 13:14, schrieb 'Tony Smith' ajsmith1968@... 
[Homebrew_PCBs]:
> The drilled holes will never line up properly, it\u2019s a fundamental
> property of universe.
> 
> When gluing use a bright light underneath so you can see both sets of
> tracks, and use something like the mounting hole outlines to align
> them.
> 
> Tony
> 
> FROM: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com]
> SENT: Sunday, 5 July 2015 3:14 PM
> TO: Homebrew PCBs
> SUBJECT: [Homebrew_PCBs] Gluing 2 single sided boards to make a double
> sided board.
> 
> Double sided boards as we all know can be a bit of a pain, the biggest
> problem is getting that precise alignment between sides correct so
> that when you drill in the center of your pad on one side, it comes
> out in the center of the pad on the other (and not, as is not
> uncommon, breaking out, and probably messing up the trace, or a trace
> nearby...). Especially if your only able to expose/imprint artwork one
> side at a time.
> 
> Even more frustrating when one side comes out perfect in part of the
> process (eg, developing) and the other side is too flawed to be
> useful, meaning you get to start from scratch again.
> 
> So, the thought randomly occurred to me today, if you could prepare,
> expose, etch, drill the two sides of a double sided board completely
> separately, and join them up at the end of the process, it would make
> getting precise alignment of those sides almost a non-issue, assuming
> you can drill even roughly vertically and hit the center of the holes
> it's just a matter of lining up the holes you drilled on each side.
> And also means that the success or failure of each side is independent
> of the other.
> 
> Of course, it does double the drilling, but that's the easy bit
> really.
> 
> This is also of course more or less how multi layer PCBs are made by
> fabricators, a stackup of already prepared pcb layers and resin
> impregnated sheets.
> 
> Single sided laminate at 0.8mm thick (and you can get down to 0.5mm)
> is available out of China for cheap.
> 
> Eg:
> 
> http://item.taobao.com/item.htm?spm=a1z10.5-c.w4002-1192550948.12.TIEXsq&id=35870048695
> [1]
> 
> http://item.taobao.com/item.htm?spm=a230r.1.14.4.VdTsRT&id=21105435798&ns=1&abbucket=3#detail
> [2]
> 
> Has anybody done this... am I reinventing a triangular wheel here, is
> it doomed to failure? Suggestions on suitable adhesive... maybe just
> spray on contact adhesive might work, it's a pretty big flat contact
> area.